| 摘要 |
PURPOSE:To realize communication at a ratio of 1 to (n), by increasing an optical peak output by lowering the light emission time ratio of a light emitting element at a transmission side, and reducing a mixed optical noise component by differentiating a reception waveform and changing a pulse width sent from a master station at every slave station at a reception side. CONSTITUTION:A leading and trailing separation circuit 1 detects the change point of a transmission data A, and generates signals B<+> and B<-> respectively. Pulse generation circuits 2 and 3 output pulses C<+> and C<-> with width t1 and t2(t1>t2) setting the signals B<+> and B<-> as reference. The pulse C<-> is outputted being delayed by (t1-t2) than the reference B<->. The pulses C<+> and C<-> are synthesized at a coupling circuit 4, then, a transmission pulse D is generated. It is possible to heighten the peak output of a beam of light by setting the width t1 and t2 less than 1/2 of the minimum pulse width of the data A. At the reception side, an electric signal D'', whose low frequency component having a large amount of mixed optical component being removed at a differentiation circuit 7, is formed as a derivative waveform E. Time interval measuring circuits 8 and 9 output signals F<+> and F<-> respectively when the interval of respective waveform E from (+) derivative to (-) derivative is within an allowable range. By setting an FF10 by the signal F<+> and resetting it by the signal F<->, a reproduction data G can be obtained.
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